Xamarin Developer (Mono for Android)

Job Description

I am looking for an experienced developer whom is comfortable with Xamarin's tools. The project would be ongoing but the first phase will be simple data entry screens using Mono for Android. The REST backend is developed so you would only consume web services and develop the UI.

Here are the requirements:
1. Must speak English
2. Must be able to work a minimum of 15 hours a week.
3. Must be fluent in C#, Linq, Xamarin, Mono for Android
4. You must understand MVC and put all common code in a Common Assembly to be consumed by all clients. Usage of mvvm is a plus+
5. Usage of ActionBarSherlock is a plus+
6. Usage of the Contacts and Calendar APIs is a plus+

Please provide me the following:
1. What is your level of experience with Xamarin Tools?
2. How many hours a week can you work?
3. What communication API do you prefer to communicate with REST services?
4. What serialization API do you prefer (i.e. Json to Object)?